The present invention is directed to the processing of acoustic signals, and more particularly, but not exclusively, relates to techniques to extract an acoustic signal from a selected source while suppressing interference from other sources using two or more microphones.
The difficulty of extracting a desired signal in the presence of interfering signals is a long-standing problem confronted by acoustic engineers. This problem impacts the design and construction of many kinds of devices such as systems for voice recognition and intelligence gathering. Especially troublesome is the separation of desired sound from unwanted sound with hearing aid devices. Generally, hearing aid devices do not permit selective amplification of a desired sound when contaminated by noise from a nearby source. This problem is even more severe when the desired sound is a speech signal and the nearby noise is also a speech signal produced by other talkers. As used herein, “noise” refers not only to random or nondeterministic signals, but also to undesired signals and signals interfering with the perception of a desired signal.